There's a mathematical theorem that backs up this cheesy slice strategy.
As just about any New Yorker will tell you, the proper way to eat a slice of pizza is by folding it in half length-wise and biting down crust-first. Not only does this seal in the toppings, but also fortifies against any flop. And as it turns out there's a long-standing mathematical theorem that backs up this cheesy slice strategy.
In a video for the Mathematical Sciences Research Institute titled "The Remarkable Way We Eat Pizza," one wacky math-loving Youtuber who goes by "Numberphile" breaks down the theoretic reasoning behind the folding of slices. Numberphile—whose real name is Cliff Stoll—credits German mathematician Carl Friedrich Gauss with the slice-strengthening logic. Gauss's "Theorema Egregium"—or "Remarkable Theorem" for us non-Latin speakers—shows how positive, negative, and zero "curvature" of objects interact with each other.
"Curvature is an intrinsic property of surfaces," Stoll says, using an orange, banana, and bagel to illustrate Gauss's point. Essentially, the Numberphile shows how object have three kinds of curves: "positive" curvature that go outward, "negative" curvature that go inward, and "zero curvature" along a flat line.
Using this theorem, Stoll shows that by taking a flat piece of pizza and curving it inward to create negative curvature against a zero curvature line, there's no scientific way a slice could flop forward according to Gauss's reasoning.
Sound complicated? Watch the Numberphile's video, then prepare to assert yourself as the smartest person in the pizza joint the next time you grab a slice.